Answer and Step-by-step explanation: The problem can be solved by using a Venn Diagram.
A Venn Diagram shows the relation between a collection of different sets.
The figure below shows:
1) Students who went only to the Homecoming = 1110
2) Students who went only to the Prom = 570
3) Students who went to both = 360
4) Students who went to none = 60
The question asks for the probability of students who went to Prom or None.
Probability of Prom =
![(570)/(2100)](https://img.qammunity.org/2021/formulas/mathematics/high-school/67ocu4lb3arjy8bn1hrluhjt8zk0seqdp2.png)
Probability of None =
![(60)/(2100)](https://img.qammunity.org/2021/formulas/mathematics/high-school/v96xc0sn8r19g11ao3c6rgbui2dwv6pkom.png)
As it is asking for "OR", use the "or rule", i.e., add the probabilities:
P(Prom or None) =
![(570)/(2100)+(60)/(2100)](https://img.qammunity.org/2021/formulas/mathematics/high-school/8rs0v1ywxwy5p64fv6c6chjh7z1kc8djyf.png)
P(Prom or None) =
![(630)/(2100)](https://img.qammunity.org/2021/formulas/mathematics/high-school/xjihfm057vip1zvcccdwld4bbit055y0c0.png)
P(Prom of None) = 0.3
The probability of a student had went to Prom or none of them is 0.3 or 30%.